Currently a system is available providing a communication service using a network configured with a plurality of different types of networks and equipped with a radio communication function such as cellular communication covering a middle and long-distance service area by one base station and a wireless Local Area Network (LAN) function covering a relatively short-distance service area. A radio communication terminal connectable with these networks also is available.
In Third Generation Partnership Project (3GPP), a wireless communication terminal and the relating communication techniques are being discussed, the wireless communication terminal having a communication function with various different types of networks such as a wireless LAN, other cellular networks (including networks before second generation, and 3GPP2 network), Worldwide Interoperability for Microwave Access (WiMAX), IEEE802.16 type wireless wide area network (WWAN) in addition to a 3GPP network (hereinafter referred to as a 3G network) as such a network configured with a plurality of different types of networks.
Particularly, discussion is being conducted to implement seamless mobility and add a mobility service to a session such as real time video or Voice over Internet Protocol (VoIP) in such different types of networks. For instance, the following Non-Patent Document 1 considers a relationship between a 3G network and a non 3G network in the different types of network environment, mainly considering a physical handover of a UE between different types of networks.
In these networks, specifications on authentication, access control and accounting also are important requirements. For instance, in a cellular network, it is being considered to perform authentication based on functions of Authentication and Key Agreement (AKA) in Universal Mobile Telecommunications System (UMTS) and GSM Subscriber Identification Module (SIM) in Global System for Mobile Communications (GSM).
Many of these functions are used for example in a communication method using EAP described in the following Non-Patent Document 2 and the following Non-Patent Document 3. For instance, in EAP-SIM described in the following Non-Patent Document 4, authentication and a session key are exchanged using information in a SIM card based on an EAP protocol. EAP-AKA described in the following Non-Patent Document 5 is expanded so as to be used in a 3G network with consideration given to compatibility with authentication in GSM, In Institute of Electrical and Electronic Engineers (IEEE) 802.1X as an authentication standard used for LAN connection also, authentication is possible using various EAPs such as EAP-Message Digest version 5 (EAP-MD5) and EAP-Transport Layer Security (EAP-TSL).
Meanwhile, the following Non-Patent Document 6 describes a technique relating to session mobility when transferring a communication session performed by a UE to another UE. This technique described in Non-Patent Document 6 is considering the continuity of a session when a part or the entire session a certain UE uses is transferred to another UE.
The following Non-Patent Document 7 and Non-Patent Document 8 are considering a mechanism to make a notice of disaster information such as an earthquake and a tsunami. A system described in Non-Patent Document 7 is to make a notice of disaster information using a 3GPP network when a disaster such as an earthquake or a tsunami occurs, which is called an Earthquake Tsunami Warning System (ETWS).
This ETWS is a system to notice a terminal (UE: User Equipment) of occurrence of a disaster, notifying the UE of a first notification (hereinafter referred to as a primary notification) on the occurrence of about 100 kinds disasters such as an earthquake and a tsunami and a second notification (hereinafter referred to as a secondary notification) on detailed information on the disasters.
More specifically, when a disaster occurs, a base station is notified of the occurrence of the disaster from the 3G network side, and the base station urgently notifies a terminal as notification information. The base station is required to notify the terminal of the first notification within 4 seconds after reception of the primary notification. For this urgent notification on the primary notification to the terminal, it is considered to make such a notification as system information. Further, as for system information such as urgent access class control due to a rapid traffic increase in a communication cell in addition to such an urgent disaster notification, a notification of a change is made within a specific period (modification period), whereby access control of a terminal can be performed more minutely.
At least a primary notification has to he provided to a terminal at the highest priority, and it is being considered to make a notification of secondary information with a Multimedia Broadcast and Multicast Service (MBMS) in the future. Further, discussion is being conducted as to whether or not a notification service of disaster information in the ETWS is to be provided not only to a macro base station (NE/eNB) but also to more local base station (HNB/HeNB). From a functional aspect, however, such a service can be provided to a local base station as well.